Switched Ethernet testing for avionics applications

Switched Ethernet is being implemented as an avionics communication architecture. A commercial standard (ARINC-664) and an aircraft vendor-specific implementation known as avionics full duplex switched Ethernet (AFDX) have been developed that defines the topology and use of switched Ethernet in an avionics application. In avionics applications, the movement of data between devices must take place in a deterministic fashion and must be delivered reliably. All aircraft flight hardware must be tested to be sure that it will communicate information properly in the switched Ethernet network. The airframe manufacture must test the integrated network to verify that all flight hardware is communicating properly. Testing and maintenance testing is required to perform data communication level testing of switched Ethernet architectures for avionics applications to insure that all communication is deterministic and reliable. This paper provides an overview of a switched Ethernet avionics network and identifies the testing challenges associated with a switched Ethernet avionics application. A practical implementation performing the required tests is discussed.     

基于DSP的固态功率控制器的设计

以提高某型飞机配电系统可靠性及灵活性为目的,设计了一种以DSP为控制内核,以μC/OS-Ⅱ实时嵌入式操作系统为软件平台的固态功率控制器。硬件选择上,系统主控制单元采用TI公司的DSP芯片TMS320F2808;功率开关芯片选用具有自保护功能的BTS724G,以期提高系统可靠性和降低功耗;采用ACS756电流传感器替代传统采样电阻。软件实现上,给出了详细的软件设计思路和系统程序设计。系统调试表明,设计的基于DSP的固态功率控制器很好地满足了负载通断要求,开关准确度和灵敏度比较高。     

Power management and distribution system for a more-electricaircraft (MADMEL)

A five-phase Power Management and Distribution System for a More-Electric Aircraft (MADMEL) program was awarded by the Air Force to Northrop/Grumman Military Aircraft Division in September 1991. The objective of the program is to design, develop, and demonstrate an advanced electrical power generation and distribution system for a More-Electric Aircraft (MEA). The MEA emphasizes the use of electrical power in place of hydraulics, pneumatic, and mechanical power to optimize the performance and life cycle cost of the aircraft. This paper presents an overview of the MADMEL program and a top-level summary of the program results, development and test of major components to date. In Phase I and Phase II studies, the electrical load requirements were established and the electrical power system architecture was defined for both near-term (NT-year 1996) and far-term (FT-year 2003) MEA application. The detailed design and specification for the Electrical Power System (EPS), its interface with the Vehicle Management System, and the test set-up were developed under Phase III. Phase IV, fabrication and testing of the subsystem level hardware, has been completed. Overall system level integration and testing, Phase V, is scheduled to be completed by September 1999     

Security, Internet connectivity and aircraft data networks

Internet connectivity which was in experimental stages only a few years ago is a reality today. Current implementations allow passengers to access Internet for pleasure and in some cases secure VPN access is provided to corporate networks. Several researchers are looking at the possibility of the existence of a total of three networks: passenger network (PN); crew network (CRN); and the control network (CON). Researchers envision an architecture where these three networks will co-exist in an airplane. The available Internet connectivity can be utilized for transporting flight critical information like cockpit flight data recorder (CFDR) data, digital flight data recorder (DFDR) data, cockpit voice recorder (CVR) data, and controller pilot data link communication. In addition, the Internet connectivity could also be used for other safety mechanisms like video surveillance and remote control of the flight. Security is one of the major concerns that affect the successful deployment of aircraft data networks (ADN) and other safety features. Several studies have been carried out to secure the network using firewalls and intrusion detection system but so far no study has focused on securing the communication channel (between the aircraft and the ground station) and its impact on the ADN. The scope of this research is to determine the viability and need of a security mechanism. The research also focuses on the performance of different security architectures and determine their usability in the framework of an ADN.     

Safe Flight 21: ground broadcast service system

The FAA-initiated Safe Flight 21 program is a cooperative government/industry effort to evaluate enhanced aerodome and aircraft capabilities based on evolving communications, navigation and surveillance (CNS) technologies. Safe Flight 21 will demonstrate the in-cockpit display of traffic, weather, terrain, and obstacle information for pilots and will provide improved information to controllers. The Ground Broadcast Service (GBS) System will act as the main communication service between the Safe Flight 21 sensors and both the avionic and ground vehicle users. The data, collected and processed by multiple sensors, is routed to the GBS System for formatting, broadcast timing coordination, filtering, and transmission to the end-users. This paper provides an overview of the GBS System as part of the FAA Safe Flight 21 program. It also presents the GBS System's complete functional requirements as well as user interface formats and protocols necessary for compliance with the Safe Flight 21 Program architecture.     

基于数字孪生的设备加工过程监测技术研究

针对典型航空产品装配生产线的生产过程中缺乏有效的人机交互手段,设备实时运行状态可视化监控程度低等问题,提出了一种基于数字孪生的加工设备运行状态监测方法,包括模型构建与优化处理、NC程序解析与加工仿真、软硬件通信与数据传输和实时仿真与数据分析.最后在某航空发动机外涵机匣装配生产线验证了该方案,可以实现NC程序加工仿真分析...     

基于虚拟仪器的飞机供电特性参数测试系统的设计

介绍了一种基于虚拟仪器PXI总线的飞机供电特性参数测试系统的设计与实现，在设计该测试系统时采用了符合PXI总线规定的硬件仪器模块，使用图形化编程语言Labview设计了飞机供电特性参数的各种测试算法，实现了多通道同时快速数据采集以及并行同步采集。通过虚拟仪器面板的交互式使用，使界面简单明了、非常便于操作。通过对国产某型飞机供电系统的测试实验。结果表明该系统设计先进、稳定可靠、测试结果达到了要求的精度，对于被测的稳态以及瞬态参数有很好的性能，具有非常广泛的应用前景。     

机载嵌入式计算机通用化BIT架构设计技术

设计开发了一种通用化BIT软件架构技术,可应用于机载嵌入式计算机.将BIT软件按照功能分为硬件驱动层、测试算法层、测试配置及控制层、应用接口层等,可极大程度实现不同硬件环境、操作系统环境下,BIT软件的可移植性,还定义了一种操作系统启动前实现硬件BIT检测的方法,可有效提高内存、CPU等硬件资源的故障检测率.     

Open systems avionics network to replace MIL-STD-1553

This paper is a proposal for a future method of avionics data communication. The need for this proposal results from the shortcomings in the current avionics architecture, video distribution network, and in the MIL-STD-1553 data communication system. The separately wired video and data communication systems can be combined to save weight, which is especially critical for rotorcraft. Aircraft, once fielded, have limited capacity for modification and improvement due to fixed computer throughput and processing performance, network bandwidth, and space available in the avionics equipment bays. The changes proposed by this paper are to be made in conjunction with the replacement of the redundant computer boxes with open system avionics functions on industry standard circuit cards. This open architecture approach was developed over the last ten years and is now being implemented in many aircraft applications including the F-22 and the RAH-66 programs. The V-22 rotorcraft, which although just entering production, is being modified for joint service customers where modern computer performance and expanded data network bandwidth is needed. The changes of this proposal will fill this need, reduce the weight of upcoming production models, and provide growth or spare capability so that additional video and data components can be added with minimal effect on existing components. This paper examines the current V-22 avionics video and data communication hardware and wiring and propose a new implementation of open system architecture standards with integrated digital video and data communication based on ANSI standard copper fibre channel     

变循环发动机完全分布式控制

采用分布式控制架构可以降低变循环发动机控制系统的重量并有利于系统的开发和扩展。提出了一种完全分布式控制架构,控制算法的计算完全分布到智能执行机构中,计算所需的参数值由智能传感器通过串行数据总线发送到智能执行机构。变循环发动机完全分布式控制系统研发的主要工作是设计分散控制算法和总线通信方案。将控制回路的耦合当作总扰动的一部分,使用线性自抗扰控制器(ADRC)观测并在控制信号中消除总扰动,实现了分散控制。在CAN总线硬件的基础上,使用CANaerospace高层协议设计了时间触发的总线通信方案。从而实现了变循环发动机完全分布式控制。在MATLAB/Simulink环境下使用TrueTime工具箱搭建了仿真系统。使用TrueTime Kernel模块仿真智能执行机构与智能传感器的计算单元,使用TrueTime Network模块仿真CAN总线,并且将线性ADRC和CANaerospace协议写入到计算单元中。仿真结果表明:所建立的变循环发动机完全分布式控制系统能够适应发动机进气状况和健康状况的大范围变化,具有较好的鲁棒性。     

Navigation system of pilotless aircraft via GPS

The pilotless aircraft has wide applications in measuring earth, surveying mineral sources, fireproofing in the forest, observing floods and so on. In this paper, after briefly introducing positioning and navigation technologies for pilotless aircraft-a new kind of navigation system for pilotless aircraft using GPS (Global Positioning System) is presented. An overall plan of the navigation system is discussed, and its technology cruxes are analysed. Its hardware and software are designed and implemented, and experimental results are given. The navigation system not only has autonomous navigation capability, but can also achieve navigation aided by telecontrol system. It can supervise flying by telemetering system and displaying predetermined air line and flight path maps on the computer monitor. It can run in simple GPS receiver mode or in the differential GPS mode by means of available telecontrol channel. These are, no doubt, of great value for the navigation of pilotless aircraft     

Design and optimization of a novel electrically controlled high pressure fuel injection system for heavy fuel aircraft piston engine

The heavy fuel compression ignition engines are widely equipped as aircraft piston engines. The fuel injection system is one of the key technologies that determines the performance of engine. One of the main challenges is to precisely control the injected fuel quantity and flow rate in the presence of pressure fluctuation. This challenge is even more serious for heavy fuel. An original design for electrically controlled high pressure fuel injection system called Multi-Pumppressure-reservoirs fuel injection System(MPS) was demonstrated to reduce the pressure fluctuation and help keep injection stable. MPS was compared with an ordinary high pressure Common Rail fuel injection System(CRS). This work established one-dimensional AMESim and mathematical models for both CRS and MPS to study the effect of different structures and geometric parameters on the pressure fluctuations. The calculations show that the average fuel pressure fluctuation of MPS can be reduced by 57% for the crankshaft speed of 1900 r/min, and the pressure fluctuation before injection reduced by 100%. It is concluded that the pressure performance of MPS is less sensitive to pressure reservoir volume than that of CRS, and there is an opportunity for further volume reduction.     

基于WPF的民机试飞数据实时监控画面开发系统设计与研究

试飞数据实时监控程序是大型民机试飞过程中不可或缺的重要支持性工具。随着机载测试系统网络化进程的不断深入,数量庞大、类型复杂的试飞参数给监控程序的开发带来了巨大的挑战。基于WPF(Windows Presentation Foundation)平台,利用XAML文件的序列化和反序列化、反射、DataBinding等技术设计了一套用于开发试飞数据实时监控程序的系统。在设计端,系统以拖拽显示控件的方式实现监控程序的快速集成和管理,将以往数周的准备周期缩短为数小时;在运行端,系统利用三层架构可实时驱动数百台监控终端,为某型客机的首飞及取证试飞提供了技术支持。     

基于航迹运行的大型客机推力管理系统需求分析

在基于航迹的运行(Trajectory Based Operation,TBO)模式中,推力管理是使飞机在安全飞行的同时,提高燃油经济性、飞行性能的关键技术。为了分析出必要可要的需求,基于民航客机推力及飞行性能原理,本文分析了基于4D-TBO的推力管理的功能及实施相关功能所必须的数据,在此基础上去设计基于航迹运行的推力管理系统(Thrust Management System,TMS)的架构,从而获得了满足未来大型先进客机飞行任务需要的TMS的重要基础信息。     

GPS autoland considerations

It is pointed out that fully automatic hands-off landing (autoland) capability for commercial aircraft, using the Global Positioning System (GPS), has not been demonstrated, and that ground multipath errors limit vertical positioning accuracy. An evolving integrated-sensor-based architecture for approach and landing, called the tunnel concept, is examined. The precise velocity information available could substantially reduce the vertical accuracy requirement for autoland     

民用飞机无线航空电子内部通信网络技术综述

民用飞机内部航空电子通信技术由无线通信部分替代有线通信,可进一步降低飞机自重,增强飞机安全性,提升民用飞机运营经济性,将成为下一代民用飞机发展的重要技术。目前,该技术尚处于研究起步阶段,为了促进该技术的发展,本文在研究国内外相关文献的基础上,对当前的研究进行概括和总结,明确民用飞机无线航空电子内部通信( WAIC )网络的定义,概括了 WAIC 网络在国内外的研究现状,分析了 WAIC 网络的特点,介绍了 WAIC 网络架构、时间同步、网络管理及网络安全等关键技术,提出了基于软件无线电平台技术开展4.2~4.4GHz 无线通信节点硬件设计的技术路径,为后续研究奠定基础。     

微波着陆地面设备维护计算机软件系统研究

维护计算机是微波着陆系统（MIS）地面设备的重要附属设备。针对微波着陆系统地面设备维护计算机的具体需求,详细分析了微波着陆系统地面设备维护计算机与相关台站的信息交互关系,介绍了维护计算机软件模块组成、通信协议、实现流程及实现的主要关键技术。该软件已成功运行于某微波着陆系统中。     

一种多核实时图像处理模块设计与实现

实时图像处理能力是嵌入式系统中影响系统性能的核心因素.为充分挖掘多核DSP性能,从计算机系统结构的角度出发,开展对多核DSP实时图像处理体系结构的研究,设计了一种基于TMS320 C6678的实时图像处理模块.采用FPGA进行实时图像的采集和缓存,利用四线RapidIO高速接口完成FPGA与DSP之间的数据传输,并设计了四级图像缓冲流水处理结构,实现了图像采集、缓存、处理和发送的并行进行.设计了一套基于数据块共享的实时图像处理多核协同处理机制,可以充分利用C6678八个核的优势,实现对图像的实时处理.     

IMA系统软件集成过程的相关考虑

IMA 架构在军机民机中的应用越来越成熟,其灵活的架构思想推动了软件往更高的可重用性方向发 展,同时也增加了软件系统的集成难度。因此,在基于IMA 软件系统开发过程中,软件集成活动越来越重要, 软件集成能力的要求越来越高。本文根据已有项目经验,结合通用集成开发环境的应用,对IMA 软件系统集 成过程提出了一系列注意事项及相关实践说明。     

Real-time ray-based channel generation and emulation for UAV communications

A real-time ray-based hardware emulator for Unmanned Aerial Vehicle (UAV) communication channels which suits for the Three-Dimensional (3D) dynamic scenarios and considers the movements of both terminals is developed in this paper. The time-variant channel parameters, i.e., ray delay, ray gain, and ray Doppler frequency are precalculated in the host by using the Ray Tracing (RT) method. Meanwhile, RT simulation dramatically increases the number of valid rays. To address the problem of resource limitation and huge computational burden in the implementation, an efficient ray coefficients generation method based on iteration is proposed and implemented. With the advantages of low cost and high flexibility, a Software Defined Radio (SDR) hardware platform is used to emulate the ray-based UAV channels by utilizing the compact architecture including the Time-Division (TD) scheme and Tapped-Delay Line (TDL) for channel convolution. Finally, hardware measurement results demonstrate that the properties of emulated channel, i.e., Power Delay Profile (PDP) and Doppler Power Spectrum Density (DPSD) consist with the simulated ones, which verifies the correctness of hardware implementation. The proposed channel emulator provides an efficient way for optimization, verification, and evaluation of UAV communication systems.